Heat exchanger

ABSTRACT

An improved heat exchanger mechanism for heating water to a predetermined temperature with steam includes means for controlling the output temperature of the heated water. The water to be heated and the steam are introduced into a heat exchange chamber and the heated water is discharged therefrom in accordance with the demand for the heated water. The means for controlling the output temperature of the heated water includes adjustable control means for mixing the heated water with unheated water and for controlling the flow of the steam to the heat exchange chamber to thereby enable the mechanism to provide the heated water at a demand location at a predetermined temperature which is easily varied by resetting the adjustable control means.

United States Patent [191 Wilson I Dec. 18, 1973 HEAT EXCHANGER [76] Inventor: Warren M. Wilson, 809 Superior Dr., Huron, Ohio 44839 [22] Filed: Apr. 27, 1970 [21] Appl. No.: 32,041

[5. U.S. Cl. 165/39 [51] Int. Cl. B60h 1/00 58 Field of Search 165/39, 40

[56] References Cited UNITED STATES PATENTS 3,391,729 7/1968 Wilson 165/39 Primary Examiner-Charles Sukalo Atrorney-Yount & Tarolli [57] ABSTRACT An improved heat exchanger mechanism for heating water to a predetermined temperature with steam includes means for controlling the output temperature of the heated water. The water to be heated and the steam are introduced into a heat exchange chamber and the heated water is discharged therefrom in accordance with the demand for the heated water. The means for controlling the output temperature of the heated water includes adjustable control means for mixing the heated water with unheated water and for controlling the flow of the steam to the heat exchange chamber to thereby enable the mechanism to provide the heated water at a demand location at a predetermined temperature which is easily varied by resetting the adjustable control means.

28 Claims, 5 Drawing Figures PAH-INIEDnEc 18 I973 GOA/067M534 SHEET 1!]? 3 I/VVENTOR WARREN M WILSON PATENTEUBEP. 18 ms I 3.779.306

INVENTOR. WARREN MI W/LSOA/ 1 f Z9 A ATTORNEYS HEAT EXCHANGER The present invention relates to a heat exchanger mechanism and, more particularly, to a heat exchanger mechanism for heating one fluid by another fluid having means for accurately controlling the output temperature of the heated fluid.

Heat exchange mechanisms-for heating one fluid, such as water, with another fluid, such as steam, are known in the prior art. However, these mechanisms do not provide for controlling the temperature of the heated fluid at an output location in a precise and easily adjustable manner and without the need for a thermostatic element.

Accordingly, it is an object of the present invention to provide a new and improved heat exchanger mechanism for heating one fluid with another fluid including means for accurately controlling the temperature of the heated fluid at an output location and enabling the temperature of the heated fluid to be precisely and easily varied.

Another object of the present invention is to provide a new and improved heat exchanger mechanism for heating one fluid with another fluid including a heat exchange chamber into which the fluid to be heated and the heating fluid are introduced and from which the heated fluid is discharged in accordance with the demand therefor, and control means for controlling the flow and pressure of the heating fluid to the heat exchange chamber to thereby precisely control the temperature of the heated fluid at an output location and wherein the control means includes a loader device and a pair of control members movable in response to the demand for the heated fluid to thereby actuate the loader device to effect a flow of the heating fluid in response to a demand for the heated fluid at a use location.

Another object of the present invention is to provide a new and improved heat exchanger mechanism, as noted in the next preceding object, wherein the pair of control members include a pair of cam members which are movable vertically to sequentially engage with an actuator assembly and impart horizontal movement thereto so that the actuator assembly imparts vertical movement to the loader device, one of the cam members being operable to impart movement to the actuator assembly to actuate the loading device to effect a constant pressure of the heating fluid to the heat exchanger chamber and the other of the. cam members being operable to impart motion to the actuator assembly to actuate the loader device to effect a variable pressure of the second fluid to the heat exchanger, and wherein the magnitude of the movement imparted to the actuator assembly is proportional to the demand for the heated fluid.

A further object of the present invention is to provide a new and improved heat exchanger mechanism, as noted in the next preceding object, wherein the pair of cam members are located externally of the heat exchange chamber and are movable vertically relative to each other so as to vary the mode of control of the loader device to thereby compensate for manufacturing inaccuracies and enable the temperature of the heated fluid to be easily varied.

A still further object of the present invention is to provide a new and improved heat exchanger mechanism for heating one fluid with another fluid including a heat exchange chamber into which the fluid to be heated and the heating fluid are introduced and from which the heated fluid is discharged in accordance with the demand therefor, and a control means for controlling the flow and pressure of the heating fluid to the heat exchange chamber to thereby precisely control the temperature of the heated fluid at an output location and wherein the control means includes a loader device and an actuator assembly located internally of the heat exchanger and which moves in response to the demand for the heated fluid to actuate the loader device and effect a flow and pressure of the heating fluid in response to a demand for the heated fluid at a use location. I

Another object of the present invention is to provide a new and improved heat exchanger mechanism, as noted in the next preceding paragraph, wherein the actuator assembly includes a cam member and a cam follower which is pivotable in response to movement of the cam member and the loader device includes a differential diaphragm which is loaded on one side thereof in response to pivotal movement of the cam follower to thereby effect the flow and pressure of the heating fluid to the heat exchange chamber and wherein the construction of the actuator assembly and differential diaphragm eliminates bleeding of fluid from the heat exchanger mechanism at a no demand condition.

Still another object of the present invention is to provide a new and improved heat exchanger mechanism for heating one fluid with another fluid wherein the mechanism includes a heat exchange chamber through which the fluid to be heated is directed by fluid conduits and into which the heating fluid is directed to effect heating of the fluid to be heated, an actuator member movable in response to the demand for the heated fluid, a mixing chamber into which the fluid conduits discharge the heated fluid, valve means for directing the flow of the fluid to be heated to the fluid conduits and to the mixing chamber, the valve means having a closed condition wherein all the fluid to be heated is directed to the fluid conduits and an open condition in which a portion of the fluid to be heated is directed to the fluid conduits and another portion is directed to the mixing chamber, and wherein the valve means includes a flow control member which is externally adjustable to thereby vary the flow of the fluid to be heated into either the mixing chamber or the fluid conduits in a predetermined manner.

A further object of the present invention is to provide a new and improved heat exchanger mechanism, as noted in the next preceding object, further including control means for controlling the flow and pressure of the heating fluid to the heat exchange chamber, the control means include a pair of cam members movable vertically in response to the demand for the heated fluid, an actuator assembly movable horizontally in response to movement of the cam members, and a loader device to which the actuator assembly imparts vertical movement thereto to effect flow and pressure of the heating fluid to the heat exchange chamber.

Further objects and advantages of the present invention will become apparent from the following detailed description of a preferred embodiment thereof made with reference to the accompanying drawings forming a part of the specification and in which:

FIG. 11 is an elevational view of the heat exchanger mechanism according to the present invention;

FIG. 2 is an axial sectional view of a portion of the heat exchanger mechanism of FIG. 1 and more fully illustrating the adjustable control means for controlling the output temperature of the heated fluid;

FIG. 3 is a top view, taken along the line 33 of FIG. 2 more fully illustrating the construction of the cam members and the actuator assembly;

FIG. 4 is a sectional view of another embodiment of the present invention and having a cam member and actuator assembly located internally of the heat exchanger; and

FIG. 5 is a sectional view, taken along the line 5-5 of FIG. 4, more fully illustrating the construction of the cam member, the actuator assembly, and the differential diaphragm of the embodiment illustrated in FIG. 4.

The present invention relates to a heat exchanger mechanism for heating one fluid with another fluid. In the illustrated embodiments, the fluids are introduced into a heat exchange chamber where the fluid to be heated is heated and discharged therefrom in accordance with the demand for the heated fluid at a location remote from the mechanism. The temperature of the heated fluid is controlled during low capacity operation of the mechanism by providing heating fluid to the heat exchange chamber at a constant pressure and by mixing a quantity of unheated fluid with the heated fluid according to a predetermined ratio to thereby reduce the temperature of the heated fluid to the temperature desired at the use location. When the mechanism is operated at a higher capacity, the temperature of the fluid to be heated is controlled by regulating the pressure of the heating fluid to the heat exchange chamber in accordance with the demand for the heated fluid. Control means are provided to control the mixing of the unheated fluid with the heated fluid and to control the pressure of the heating fluid to the heat exchange chamber to thereby control the output temperature of the heated fluid.

The embodiment of the present invention illustrated in FIGS. 1-3 comprises a heat exchanger mechanism which is suitable for heating a variety of fluids with a variety of other fluids, but will be hereinafter described as heating water with steam. The heat exchanger mechanism 10, generally illustrated in FIG. 1, includes a heat exchange chamber 44 into which water is introduced through an inlet water conduit 14 and heated by steam introduced through a steam conduit 16. The water is heated by the steam as it circulates through the heat exchange chamber 44 and the heated water is discharged from the apparatus through a water outlet conduit 22. A valve, not shown, regulates the discharge of the water through the conduit 22 and establishes a demand for hot water on the heat exchanger mechanism 10. Steam condensate is discharged from the heat exchange chamber 44 through a steam condensate line 18. The steam condensate line 18 has a steam trap 20 which is preferably vented to the atmosphere so as to maintain a minimum back pressure on the steam in the heat exchange chamber 44.

The heat exchanger mechanism 10 includes control means 24 which operate to control a steam valve 26 to thereby control the flow of steam through conduit 16. Steam valve 26 is a commercially available reducing valve which is operated by differences in the fluid pressure acting on opposite sides of a diaphragm actuator 27 to control the steam flow therethrough. One side of the diaphragm of the steam valve 26 is loaded by steam in conduit 16 and the other side of the diaphragm is loaded by the control means 24 in accordance with the demand for hot water placed on the mechanism 10.

The heat exchanger mechanism 10 comprises a housing or shell 30. The housing 30 is preferably of a generally cylindrical shape and is formed in two parts, 30a and 30b. Parts 30a and 30b are detachably connected by a plurality of suitable fasteners such as the bolts 31. The two-piece construction permits the heating apparatus to be easily disassembled for servicing.

The water to be heated is introduced into the heat exchanger mechanism 10 by the inlet water conduit 14. The inlet water conduit 14 communicates with a chamber 34 (FIG. 2) of a bypass means or bypass valve 36. The chamber 34 has an annular opening 32 therein which communicates with an arcuate water inlet chamber 38 provided in the lower part of the housing 30b. The arcuate water inlet chamber 38 is formed in part by an annular baffle member 52 having a flange portion 43 which is connected to the upper part of the housing 30b by compression. The arcuate water inlet chamber 38 communicates at its lower end with fluid conduit means 42 which circulates the water to be heated through the heat exchange chamber 44. The water is heated by the steam in the heat exchange chamber 44 as it circulates through the fluid conduit means 42.

The heat exchange chamber 44 is similar to the heat exchanger illustrated in applicants copending application Ser. No.868,428. As disclosed in the copending application, the fluid conduit means 42 comprises a circular array of spaced tubular members 46 (FIG. 1) arranged in circular rows concentric with the central longitudinal axis of the heat exchange chamber 44. The tubular members 46 are open-ended tubes supported by the support members 48 and 50. The members 48 and 50 cooperate to maintain the tubes 46 in a properly spaced relationship so that steam can flow about the tubes and also prevent steam leakage from the heat exchange chamber 44.

The heat exchange chamber 44 is in part defined by a pair of annular baffle members 52 and 54. The baffle members 52 and 54 cooperate with the tubes 46 to direct the water to flow in parallel paths in opposite directions through the tubes 46. The water to be heated flows in a first direction through certain of the tubes 46 and in an opposite direction through other of the tubes 46. The described flow of water through the chamber 44 permits the chamber 44 to be more compact in length and yet provides efficient heat exchange between the steam and the water to provide heated water at the desired temperature and volume.

The water flows through the heat exchange chamber 44 four times as is more fully described in applicant's copending application Ser. No. 868,428. The water flows from the arcuate chamber 38 formed in part by the upper annular baffle member 52 downwardly through a portion of the tubes 46 to the lower annular baffle member 54. The lower annular baffle member 54 directs the water to flow upwardly through another group of tubes 46 to another arcuate chamber formed 4 in part by the upper annular baffle member 52. The

let portion of the upper annular baffle member 52 into a mixing'chamber 58 located in the lower portion 30b of the housing.

The steam is introduced into the heat exchange chamber 44 through a suitable inlet opening 116a disposed in the wall of the lower housing portion 30a and into which steam conduit 16 is suitably connected. The steam in the heat exchange chamber 44 flows about the spaced tubes 46 and is discharged from the heat exchange chamber 44 through a condensate discharge opening 60 provided in the lower part of the lower annular baffle member 54 and to which the steam condensate discharge conduit 18 is suitable connected. As the water flows through the tubes 46 in the heat exchange chamber 44, the water is heated by the steam which flows therethrough. The heated water is continually mixed as it flows into the chambers in the baffle members and is then discharged from the upper end of the inner group of tubes 46a into a mixing area or chamber 58.

It has been discovered that during low duty operation of the heat exchange mechanism 10, the temperature of the water discharged therefrom can be controlled by mixing colder or unheated water with the water which has been heated in the heat exchange chamber 44. Although the limits of the low duty operation of the mechanism are adjustable, the range found very suitable for controlling water temperature by mixing is from start-up to about 40 percent of capacity. The high duty operation would be from about 40 percent to 100 percent of capacity of the heat exchanger mechanism 110. During low duty operation, the pressure of the steam in the heat exchange chamber 44 is maintained substantially constant and by mixing a predetermined volume of cold water with the heated water, the temperature of the water discharged from the heat exchanger mechanism 10 can be regulated. Water of a predetermined temperature is then discharged via the port 220 which is connected to the outlet conduit 22 which directs the flow of the water to a use location. It should be realized that while the steam pressure is constant, the steam flow rate will not be constant. This is due to the fact that as the flow of water through the heat exchange chamber 44 increases the steam condensing rate will also increase. An increase in the steam condensing rate will cause the steam flow rate to also increase so as to maintain a constant pressure in the heat exchange chamber. The diaphragm actuator 27 will act to keep the steam pressure constant as the steam condensating rate increases.

The cold water used for mixing is preferably obtained from the inlet chamber 34. The water in the inlet chamber 34 is bypassed into the mixing chamber 58 through a fluid passageway 64. Fluid passageway 64 is defined by a tubular member 66 which is received in an opening provided in the wall of the upper annular baffle member 52. The flow of cold water through the passageway 64 is controlled by the mixing regulator or bypass valve 36. The valve 36 has a cage-type construction so that the whole valve assembly can be readily removed by unbolting the cover to thus facilitate servicing of the structure.

The mixing regulator 36 includes a flow control member 68 to control the flow of the cold water into the mixing chamber 58. The flow control member 68 is located in an inlet 70 disposed between the passageway 64 and the mixing chamber 58. The flow control member 68 is of a size and configuration which has a close sliding fit within the tubular member 66 and is op erable to engage with the surface 72 of the tubular member 66 to close the inlet 70 and block the flow of cold water into the mixing chamber 58.

The flow control member 68 has a cam follower 74 affixed thereto and which extends from one end thereof to engage with a cam member 80. A spring member 76 biases the flow control member 68 toward the surface 72 and maintains the cam follower 74 in engagement with the cam member 80. The cam cooperates with the spring 76 to control the position of the flow control member 68 relative to the tubular member 66 and the surface 72 to thereby control the cross-sectional area of the inlet 70 and the volume of cold water that is mixed with the heated water in the mixing chamber 58. The position of the flow control member 68 changes as the demand for hot water changes The coil spring member 76 is biased leftwardly by the seat 82 which is movable within the tubular member 66 by the seat adjustment stem 78. The seat adjustment stem 78 extends through the wall of the heat exchanger mechanism and has a nut portion 78a attached to the protruding end thereof. The other end of the seat adjustment stem 78 is suitably pinned into the seat 82 and cage 66 by pin 79. Thus, it can be seen that by removing the nut portion 78a, the seat adjustment stem 78 and the seat 82 can be moved to the left or to the right depending on the direction of rotation of the stem 78 to thereby vary the area of the annular opening 70. Adjustment of the position of the seat 82 varies the set point of the hot water by controlling the volume of cold water that flows into the mixing chamber 58. it should be apparent that movement of the seat adjustment stem 78 and the seat 82 vary the annular opening 70 to the mixing chamber 58 by varying the relative position of the flow control member 68 in relation to cage member 66.

As the demand for hot water is initially established, the volume of cold water mixed with the heated water represents a relatively large percentage of the total volume of water discharged from the heat exchanger 10. It is necessary to provide such a ratio at start-up to bring the water to the desired temperature, since the heated water is always above the desired temperature at start-up conditions. As the demand for hot water increases, a greater volume of cold water is mixed with the heated water, but the volume of cold water represents a smaller percentage of the now higher total volume of water discharged from the mechanism 10. The mechanism 10 is preferably set so that the mixing stops when it is operating at about 40 percent of the capacity and above.

The position of the cam member 80 controls the position of the valve member 68 to thereby control the flow of cold water into the mixing chamber 58. The cam member 80 moves vertically relative to the cam follower 74 as will be disclosed hereinbelow in response to demand for hot water. The cam 80 comprises surface portions 81 and 82. As the cam 80 moves vertically, the cam follower 74 sequentially engages the cam surface portions 811 and 82 and provides for positioning of the flow control member 68 relative to the tubular member 66 to open and close the annular inlet 70 to the mixing chamber 58 to thereby control the flow of cold water into the mixing chamber 58.

The cam 80 is moved vertically relative to the cam follower 74 upon movement of a piston member 90. The piston 90 is mounted for reciprocation in the upper portion of the housing 30b and moves in response to a difference in water pressure acting on the upper and lower sides thereof caused by a change in demand for hot water. The piston 90 has a skirt portion 92 which has a complementary close sliding fit with the inner surface of the upper portion of the housing 301; so as to effectively seal portions of the upper housing 30b on opposite sides thereof. The lower end of the piston skirt 92 seats on the flange portion 43 of the annular baffle 52 when there is no demand on the mechanism 10. In this position, the relative arrangement of the cam 80 and the cam follower 74 is that shown in FIG. 2.

As the demand for hot water is established, the piston 90 moves away from the flange 43 and effects upward movement of the cam 80 which is connected to the piston 90 by a piston rod 94. The piston rod 94 extends from the cam member 80 through the piston 90, through the piston stem guide 96 mounted on the upper portion of the housing and is suitably fastened to a piston stem offset support 98. A spacer sleeve member 94a extends between the piston 90 and the cam 80 to prevent relative movement between the piston 90 and the cam 80.

The piston rod 94 extends through the piston stem offset support 98 and is affixed to same via a suitable lock nut. A spring thrust bearing 100 is suitably fixed to the upper part of the housing by the bolts 101, more fully illustrated in FIG. 3. Disposed between the spring thrust bearing 100 and the piston offset support 98 is a range spring 102. The range spring 102 is an expansion spring and acts on the piston offset support 98 to bias the support and the piston member 90 downwardly.

At a stagnant or no demand" condition, the cam surface portion 81 is in engagement with the cam follower 74 and the water pressure on either side of the piston 90 is equal. This allows the range spring 102 and the weight of the piston assembly to hold the piston at its lowermost position as illustrated in FIG. 2. As a demand for hot water is established at the outlet 22a, the piston member 90 moves upwardly due to the lower pressure at the outlet 22a. The cam 80 moves upwardly with the piston member 90 and the cam follower 74 engages the inclined portion 82 of the cam 80 which allows the flow control member 68 to start to close the annular opening 70 to the mixing chamber 58. The cam surface portion 82 gradually moves the flow control member 68 toward the surface 72 of the tubular member 66 thereby reducing the flow of fluid through passageway 70 into the mixing chamber 58 as the demand for hot water increases.

When the apparatus is operated preferably at about 40 percent capacity, the piston 90 moves the cam 80 so that the cam follower 74 engages with the lower portion of the cam surface 82. When the cam follower 74 engages with the lower portion of the cam surface 82, the flow control member 68 moves into engagement with the portion 72 of the tubular member 66 thus closing the inlet 70 to stop the flow of cold water into the mixing chamber 58 so that the mixing operation is discontinued. As the demand for water decreases, a reverse downward movement of the cam 80 occurs and the flow control member 68 will move away from the surface 72 of the tubular member 66 to allow mixing to reoccur. It should be apparent that the temperature of the water in the mixing chamber 58 is controlled by operation of the mixing regulator 36 during low duty operation of the mechanism 10 and that the water temperature can be adjusted by rotating the seat adjustment stem 78 to regulate the cross-sectional area of the inlet and thus control the flow of cold water to the mixing chamber 58.

After the water reaches the desired temperature in the mixing chamber 58, the water is directed into an outlet chamber 1 10 from which it is discharged through the opening 22a into the water outlet line 22. The rate at which the heated water is discharged from the outlet chamber is controlled by a valve 112. The valve 112 includes a tubular conduit 114 through which water is directed to the outlet chamber 110. A stationary valve member 116 is arranged within the conduit 114 and is supported by a valve stem 118 adjustably connected to the upper part of the housing 30b. The conduit 114 has external threads disposed on a lower portion thereof which are engageable with a nut 120. The lower portion of the tubular conduit 114 extends through the piston member 90 and the nut member 120 is threadably secured thereon. The tubular conduit member 114 includes a flange portion 122 which is clamped into engagement with the upper portion of the piston member 90 by tightening of the nut 120 on the opposite side of the piston 90. Thus, the combination of the flange portion 122 and the nut 120 securely affix the tubular portion 114 to the piston 90 for movement therewith and the conduit 114 moves with the piston 90 relative to the valve member 116 to regulate the flow of the heated fluid through the valve 112.

The conduit 114 has a cylindrical portion 114a and a frustro-conical shaped portion 1l4b. When the valve member 116 is in engagement with the cylindrical portion 114a, as illustrated in FIG. 2, fluid flow through the valve 112 is blocked. When a demand for hot water is established, the conduit 114 moves upwardly with the piston 90 relative to the valve member 116 so that the valve member 116 no longer engages with the cylindrical portion 114a and water is permitted to flow about the valve member 116 through the conduit 114 to the outlet chamber 110.

The valve stem 118 is threadably secured to the upper portion of the housing 30b and a nut 117 is secured to the outer extending portion of the valve stem 118. Both the nut 117 and the upper portion of the valve stem 118 have engaging threads and removal of the nut 117 permits stem 118 to be rotated and this effects vertical axial movement of the valve stem 118 and, thus, valve member 116 moves relative to the tubular conduit 114.

When a demand for hot water occurs in the outlet 22a, a pressure differential across the piston 90 is induced and, due to the lap between the valve member 1 16 and the cylindrical portion of the conduit 114a, the piston 90 must move a finite distance against the force of the range spring 102 before flow takes place. This initial movement without flow is used to establish the necessary constant steam pressure in the heat exchange chamber 44 to cope with the condensate back pressure at the installation. The initial movement of the piston 90 also establishes a pressure differential across the piston which balances the forces acting on either side of the piston and produces an area for flow through the valve 112 to just satisfy the demand for hot water at the use location. From a minimum demand for hot water, any further demand produces a larger pressure differential across the piston 90. Thus, for any demand, only one piston position will satisfy all forces involved so that the correct area for flow based on the pressure differential across the piston will be established.

It should be realized that by varying the position of the fixed valve member 116, the lap between the tube 114 and the fixed valve member 116 can be varied to compensate for the necessary steam back pressure in the pressure chamber. For example, if there were no condensate back pressure in the heat exchanger, i.e., where the condensate was discharged directly to the atmosphere, less lap would be desired between the valve member 116 and the tube 114. But where the condensate back pressure is greater, a greater lap would be needed. Thus, the stem member 118 can be used to adjust the relative lap between the fixed valve member 116 and the tubular conduit 114. Moreover, the force required to start movement of the piston can be varied by adjusting the force exerted by the range spring 102 which biases the piston rod 94 downwardly.

A leak-off pathway l30b is provided between the upper portion of the housing member 30a and the tubular conduit 114 to allow a small flow of water between the outlet chamber 110 and the upper portion of the piston member 90. The leak-off passageway on the external guiding surface of the frustro-conical metering tube 114 is essential for proper operation of the piston 90 which necessarily must have some leakage around it. Thus, any water that might possibly be disposed above the piston 90 and which could become trapped between the upper portion of the piston member 90 and the upper portion of the housing 30b and which could act as a damper mechanism to prevent movement of the piston 90, will flow through the leak-off passageway 130 and, therefore, allow movement of the piston 90.

Upon demand for hot water, the water pressure above piston 90 drops considerably and the piston 90 and the conduit 114 move upward in the housing 30b due to the substantial water pressure acting on the underside of the piston 90. Upward movement of the conduit 1 14 opens valve 1 12 and water flows therethrough. When the demand for hot water is reduced, the water pressure acting on the upper side of the piston 90 increases and results in a downward movement of the piston 90 toward its neutral position which will reduce flow through the valve 112. It should be obvious that the pressure acting on the underside of the piston 90 is the water pressure flowing from the tubes 46 to the mixing chamber 58. When the demand for water is terminated, the piston 90 will move to its neutral position, as illustrated in FIG. 2, and the valve 112 will be closed.

During low duty operations of the heating apparatus 10, the aforedescribed operation is all that is required to maintain a preset temperature of the heated water since the steam pressure in the heat exchange chamber 44 remains essentially constant up to this point. But as the demand for water exceeds a predetermined point, preferably such as the 40 percent of capacity, it is necessary to increase the steam pressure in the heat exchange chamber 44 since the increased flow of water through the tubes 46 condenses the steam faster. Moreover, at this point, it is desired to cease blending of the hot water with cold water in the mixing chamber 58. Therefore, a control means 24 is provided which operates to increase the pressure in the heat exchange chamber 44 by increasing the flow of steam through the steam valve 26.

The control means 24 comprises a cam actuated loader device or loader valve which regulates the loading of one side of the diaphragm of the steam valve 26. The valve 130 establishes a particular pressure on the control fluid in the line 132 to load one side of the diaphragm of the steam valve 26 to thereby control the flow of steam through the steam valve 26. In the illustrated embodiment, the control fluid utilized is water which is directed to the valve 130 through a line 131 from the water inlet line 14.

The cam actuated loader valve 130 is supported adjacent the upper portion of the housing 30b by a support structure 140. The loader valve 130 is affixed to the support structure by the special adaptor nut 130a, and support structure 140 is rigidly affixed to the upper part of the housing member by fastening means such as the bolt 134. The valve 130 is operated in response to a demand for hot water by a cam actuator assembly 136 illustrated in FIGS. 2 and 3.

The cam actuator assembly includes a cam support post 138 which is threaded into the piston stem offset support 98 which moves vertically when the piston stem 94 effects movement thereof due to vertical movement of the piston 90 when a demand for hot water is established. Suitably disposed on the cam support post 138 is a pair of cam members 140 and 142, respectively. The upper cam 140 is attachably secured by a pair of lock screws 141 to the cam support post 138. The lock screws 141 provide for adjustment of the cam 140 vertically along the support post 138 to permit proper positioning thereof to compensate for manufacturing inaccuracies. The cam 140 includes a cam surface 140a thereon which effects movement of the actuator assembly 136 to bias the loader device 130. The cam surface 140a engages with the cam follower or roller secured on a thrust rod 154 to effect horizontal movement of the thrust rod 154 when the cam 140 moves in an upward direction. The adjustment provided by the lock screws 141 permits positioning on the cam surface 140a relative to the follower 150 to set the starting point of operation of the loader valve assembly 131) as described more fully hereinbelow.

The lower cam member 142 is also adjustable vertically along the support post 138 and includes the arm 143 having a cam surface 143a thereon. The arm 143 is pivotally mounted on the cam 142 and the angular relationship of the cam surface 143a relative to the cam 142 is controlled by an eccentric 144 mounted on the cam support post 138. The eccentric 144 is rotatable about the post 138 to control the incline of the cam surface 143a and has a set screw 144a therein which is operable to fix the eccentric relative to the arm 143 and the post 138 to thereby fix the arm 143 in any one of a plurality of positions.

Upon initial movement of the piston 90, the cam support post 138 and the pair of cams 140 and 142 are moved upwardly by upward movement of the piston stem offset support 98. Initial movement of the cam support post 138 in an upward vertical direction causes the surface 140a of the upper cam 140 to effect horizontal movement of a thrust rod 154 of the actuator assembly 136. The horizontal movement is effected when the cam roller 150, which is supported by a cam roller support 152, engages with the cam surface 140a.

Engagement of the cam roller 150 with the surface 140a effects movement of the cam roller and the cam roller support 152 to the left as viewed in FIG. 2.

The cam roller support 152 is suitably affixed to the thrust rod 154 by means of a pin 157. The thrust rod 154 has a keyway 156 therein which engages with a keyway guide screw 158 supported in a support structure 160 and which guides the movement of the thrust rod 154 relative to the support structure 160. A cam adjustment screw 145 is threaded into the thrust rod 154 and positioned by a nut member 162 so that the cam adjustment screw extends from the thrust rod 154. It should be evident that the thrust rod 154 moves a predetermined distance to the left, as shown in FIG. 2, when the cam surface 140a engages with the cam roller 150.

Attached to the support structure 160 by means of a support member 172 is a roller assembly 170. The roller assembly is pivotally mounted on the support member 172 by means of a pin 174 and includes a pair of rollers 176 and 178. Movement of the thrust rod 154 causes the cam adjustment screw 145 to engage with the roller 176 and causes the roller assembly to pivot about the pivot pin 174. The pivoting motion of the roller assembly 170 in a counterclockwise direction causes the roller 178 to move vertically in a downward direction against a loader adjustment screw 180 to thereby actuate the loader device 130. Thus, it should be apparent that vertical movement of the cam surface 140a relative to the follower 150 effects vertical movement of the loader adjustment screw 180 of the loader valve 130 to open the steam valve 26 and allow steam to flow into the pressure chamber 44. The cam member 140 biases the loader screw a fixed distance so that further upward movement of the cam 140 does not effect an increase in the pressure of steam to the pressure chamber 44. It should be realized that the cam surface 140a only controls the loader valve during initial movements of the piston member 90 and effects a constant pressure of steam in the pressure chamber 44. Further upward movement of the piston 90 effected by operation of the heat exchanger at greater than 40 percent of its capacity will effect engagement of the cam follower 155 with the cam surface 143a. Since the cam surface 143a is inclined relative to the cam follower 155, it should be apparent that as the cam surface 143a moves upwardly the magnitude of movement imparted to the thrust rod 154 will increase directly with the movement of the cam surface 143a upwardly. Since the magnitude of movement of the thrust rod 154 controls the steam pressure in the heat exchange chamber, the greater the magnitude of movement imparted to the thrust rod 154 the greater the steam pressure in the heat exchange chamber 44. Accordingly, it should be obvious that when the cam surface 143a engages with the cam follower 155 the steam pressure in the heat exchange chamber 44 will be directly proportional to the demand for hot water at the use location. This is due to the fact that as the demand for hot water increases, the piston 90 will continue to move upwardly and the cam 143 will also continue to move upwardly to thereby increase the pressure on the steam valve diaphragm which effects an increase in steam pressure in the heat exchange chamber 44. I

When there is no demand for water, the cam 140 engages the follower 150 as shown in FIG. 2 and the loader stem 180 is not biased downwardly. This relation sets the loader valve so that the fluid pressure in line 132 closes the steam valve 26. As the demand for water is initiated, the piston 90 moves vertically as described heretofore and the cam surface a engages with the cam follower and moves the valve stem 180 downwardly as viewed in FIG. 2. Valve 130 is now set to load the steam valve 26 and. establish a predetermined constant steam pressure in the heat exchange chamber 44. Steam pressure will be maintained as long as the heat exchanger is operating at less than 40 percent of its capacity. When the mechanism is operating at high duty, which is preferably 40 l00 percent of capacity, the cam follower will engage with the cam surface 143a to further bias the valve stem in a downwardly direction. As the cam follower 155 moves along the surface 143a, the valve 130 will be biased to set the steam valve 26 to increase the pressure in the heat exchange chamber 44 in relationship to the position of the cam follower 155 on the cam surface 143a.

To cope with the drop-offin water temperature at the point where blending ceases, the lower external cam surface 143a engages with the lower cam follower 155 to begin increasing the steam pressure to the heat exchanger. The rate of increase in steam pressure as controlled by the movement of the piston 90 can be controlled by adjusting the slope of the lower external cam 143. This is accomplished by rotation of the cam eccentric 144 which will control the slope of the cam surface 143a.

If it is desired to change the temperature of the hot water as it is delivered from the outlet 22a, the seat adjustment stem 78 may be rotated. With the right-hand threads, clockwise movement of the stem 78 will increase the valve opening 70 and lower the water temperature. The ratio of the change in the blending of cold water with the heated water for various exit water temperature settings will produce parallel cam curves so that one cam curve would suffice to produce various exit water temperatures with the adjustment of the valve stem 78. However, movement of the flow control member 68 would change the point where blending ceases, but this can be compensated for by adjusting the slope of the lower external cam 143 or moving the cam member 142 vertically on the support post 138, as described hereinabove, to effect engagement of the cam follower 155 at a different position, and thus effect an increase in the steam pressure at the new point where blending ceases.

The steam pressure required to produce a particular rate of condensation of steam in the heat exchange chamber 44 should be set in relation to the back pressure on the steam in the heat exchange chamber. The difference between the steam pressure and the back pressure in chamber 44 should be such as to provide a desired condensation rate. During low capacity operations of mechanism 10, a relatively low constant steam pressure should be provided if the mechanism 10 is in a system providing very little back pressure, such as the system illustrated where the steam trap 20 is vented to the atmosphere. However, if the mechanism 10 is employed in a system which produces a substantial back pressure on the steam in chamber 44, such a system will have a close steam cycle and the steam pressure will have to be increased accordingly.

The present invention provides an external adjustment of the fixed valve member 116 of the valve 112 so that the system may operate in either of the systems described heretobefore. The adjustment provides for changing the setting of the valve 112 so that less piston stroke is required when the piston moves to a minimum flow condition. This would be used for a zero pounds per square inch steam condensate back pressure where the condensate was discharged to the atmosphere. As the condensate back pressure is increased, greater lap between the parts 116 and 114 would be needed. Moreover, the upper external cam 140 can be slid along its post and in conjunction with the piston movement, produce the correct loader steam pressure on part 180 to effect activation of the loader valve 130 to assure the correct constant steam pressure to the heater for operation when the heat exchanger is operating at less than 40 percent of its capacity.

It should be apparent that the heat exchanger mecha nism operates in three integral phases. In phase number one there is no flow of water and there is no flow of steam to the heat exchange chamber. This minimizes fouling of the tubes and overheating of the water disposed in the heat exchange chamber. Phase number two is when the duty of the heat exchanger is somewhere between zero and approximately 40 percent of the rate of capacity. During this phase, the controlled steam pressure is held at a fixed constant value and the mixing of the heated water and the unheated water occur in a controlled relationship. The mixing does not necessarily take place at a constant rate as the mixing will be controlled by movement of the cam member 80. By adjusting the external cam members, any reasonable steam pressure to the heat exchange chamber at a constant rate can be obtained. Phase number three is when the duty of theheat exchanger is between approximately 40 to 100 percent of the rated capacity. I-Iere mixing of the heated and unheated fluids ceases altogether and the control of the steam presure to the heat exchanger becomes the sole control mode. While 40 percent has been suggested as the preferable range where blending should cease, the adjustable position of the lower external cam and the adjustable position of the mixing valve can be used to vary this range.

The embodiment of the invention illustrated in FIGS. 4 and S is a heat exchanger mechanism which is similar to the heat exchanger mechanism illustrated in FIGS. 1-3 but includes a control means 202 which is located internally of the housing 30b. Like parts in FIGS. 4 and 5 have been designated with like numerals and only the upper portion of the housing 30b and the control means disposed therein have been illustrated as the heat exchange chamber and the bypass valve assembly are analogous to those illustrated in FIG. 2. Essentially the loader valve 218 performs the same function as loader 130.

The piston 90 is normally biased downwardly to a noflow condition, as illustrated in FIG. 4, by a range spring 204. The range spring 204 is an expansion spring and extends between an upper portion of the piston 90 and a thrust collar 206 which is externally threaded upon a tubular conduit 208. The tubular conduit 208 is secured to the upper portion of the housing 30b and directs the flow of the water through the conduit 22 to a demand location. The tubular conduit 114 of the valve 112 is slidably received in one end of the conduit 208 and the conduit 208 guides the movement of the conduit 114 with the piston 90. It should be apparent that the force which the spring 204 exerts on the piston member 90 can be varied by rotating the collar 206 re]- ative to the conduit 208 to thereby vary the compres sion of the spring 204. The range spring 204 acts in an analogous fashion to the range spring 102 illustrated in FIG. 2, to bias the piston to its no-flow position.

The valve stem 118 of the valve 112 is threadably secured to a bracket 212 which is affixed to the upper portion of the housing 30b. A nut 214 is secured to the outer extending portion of the valve stem 118 and removal of the nut 214 permits the valve stem 118 to be rotated and thus effects vertical axial movement of the valve member 116 relative to the tubular conduit 114.

The control means 202 comprises a cam actuated actuator assembly 210 which when moved by a cam member 216 effects loading of a loader valve 218. The valve 218 establishes a particular pressure in the line 132 to load one side of the diaphragm of steam valve 26 to thereby control the flow of steam through the steam valve 26 to the heat exchange chamber 44. In the illustrated embodiment, the control fluid utilized is water which is directed to the valve 218 through a line 220 from the water inlet 14. The loader valve 218 is supported in an opening 222 in the upper portion 30b of the housing. The valve 218 includes a flanged portion 224 which is operable to be bolted to the housing 30b by a plurality of bolts 226 to secure the valve 218 to housing 30b. When the bolts 226 are tightened the valve 218 is securely held in the opening 222 and a fluid tight seal exists between the opening 222 and the valve 218 to thereby prevent the flow of fluid from the heat exchanger mechanism.

The valve 218 is operated by the actuator assembly 210 in response to a demand for hot water. The actuator assembly 210 includes a support member 230 which supports a pair of cam followers 234 and 236 thereon. The support member 230 is pivotally associated with a support structure which includes a threaded portion 242 thereon which is receivable in a threaded opening 245 disposed in the bottom 240 of the valve member 218. The support structure 238 rotatably supports a shaft 232 on one end thereof and upon which the support member 230 is pivotally supported.

The pair of cam followers 234 and 236 are supported by the support member 230 and are located directly above the cam member 216 which is secured to the piston 90. Movement of piston 90 in an upwardly direction as described hereinabove effects engagement of the cam member 216 with the cam followers 234 and 236. When the cam followers 234 and 236 engage with the cam member 216 upon movement thereof, the cam member 216 will effect movement of the cam followers to the left as viewed in FIG. 5 to thereby pivot the support structure 230 about the shaft 232.

The cam 216 includes a plurality of surfaces 244, 246 and 248 thereon which are operable to sequentially engage with the cam followers 234 and 236. Initial vertical movement of the cam 216 with the piston 90 will effect engagement of the surface 244 with the cam follower 234. The cam follower 234 will then slide from the surface 244 to the surface 246 to effect pivotable movement of a predetermined magnitude of the support member 230. When the cam follower 234 is engaged with surface 246 of the cam member 216 further upward movement of the cam member 216 will not effect further rotation of the support member 230 until the cam follower 236 engages with the surface 248 of the cam member 216. Thus, it should be apparent that initial movement of the cam member 216 will effect a pivotable movement of a predetermined magnitude of the support member 230 which will accordingly move the cam follower 236 in a clockwise direction away from its position illustrated in FIG. 5. The support member 230 will remain in its position to which it has been pivoted initially until the cam follower 236 engages with surface 248 upon further upward movement of the cam member 216. When the cam follower 236 engages with the cam surface 248 further pivotable movement of the support member 230 in a clockwise direction will be effected and the magnitude of the pivotable movement of the support member 230 will be directly proportional to the movement of the cam member 216. It should be apparent that when the cam follower 236 is engaged with the cam surface 248, the greater the vertical movement of the cam member 216 the greater the pivotable movement of the support member.

An actuator member 250 is pivotably attached by a pin 254 to an arm 252 which extends from an upper portion of the support member 230. The actuator member 250 includes a seat 256 therein which receives one end of an actuator stem 258. Pivotal movement of the support member 230 about the shaft 232 effects an upward pivotal movement of the actuator member 250. The upward pivotal movement of the actuator member 250 will raise the actuator stem 258 to effect loading of a differential diaphragm 260 disposed in the valve 218. The actuator stem 258 is normally biased in a downwardly direction by an expansion spring 262 which is disposed between a shoulder portion 264 of the actuator stem and a seat 266 disposed on the differential diaphragm 260. Upward movement of the actuator stern 258 will compress the spring 262 to load the bottom side of the differential diaphragm 260.

Supported on the differential diaphragm 260 is a seat 268 upon which one end of a valve stem 270 is seated. The valve stem 270 is associated with a valve member 272 which cooperates with a valve seat 274 in the upper end of the valve 218 to control the fluid flow through an opening 280. The valve member 272 is normally biased in a downwardly fashion by a valve spring 276 which is disposed between a shoulder portion 278 of the valve member 218 and a shoulder 279 of the valve member 272. The spring 276 is an expansion spring and normally holds the valve member 272 against the opening 280 to thereby prohibit the flow of fluid from the source of fluid 220 through the opening 280 to the valve 218.

An expansion spring 282 is disposed between a surface portion 284 of the valve 218 and the seat 268 so as to cooperate with the spring 262 to load the differential disphragm 260. Upward movement of the actuator stern 258 compresses spring 262 to increase the load on the bottom side of the differential diaphragm 260 and causes the diaphragm to bend in a upwardly direction against the force of the spring 282. This effects upward movement of the seat 268 to thereby move the valve member 272 upwardly against the force of the spring 276 and away from the opening 280 to thereby enable fluid to flow from the line 220 through the opening 280 and into a chamber 286 disposed above the differential diaphragm 260. The fluid then flows from the chamber 286, through an opening 288 therein, to the line 132 to load the steam valve 26. When the steam valve 26 is loaded steam will flow into the heat exchange chamber as explained hereinabove.

It should be realized that the magnitude of movement of the valve member 272 is directly related to the rotation of the support member 230 and also that the movement of the valve member 272 directly controls the pressure in the line 132 which controls the pressure of the steam in the heat exchange chamber 44. Upon initial movement of the cam member 216 initial rotation of the support member 230 will be effected and the valve 272 will be moved a predetermined distance away from the opening 280 to set the pressure in the control line 132 to thereby control the steam pressure in the heat exchange chamber 44. The steam pressure in the heat exchange chamber 44 will be maintained constant upon further movement of the piston member until the cam follower 236 engages with the cam surface 248. When the cam surface 248 engages with the cam follower 236 further upward movement of the cam member 216 will cause further rotation of the support member 230 to thereby effect further upward movement of the valve 272 away from the opening 280. This, of course, will cause an increase in pressure in the control line 132 to effect further opening of the steam valve 26 to thereby effect an increase in steam pressure in the heating exchange chamber 44.

A valve seat 264a is provided at the enlargement of the actuator stem 258, which seats against bottom 240 of the valve member 218. Actuator stem 258 is provided with an extremely long and close fit between valve bottom 240. Under no-demand condition, springs 282 and 262 cooperate to seat 264a against bottom 240 and prevent leakage of water from the heat exchanger. Under any demand condition, the long close fit of actuator stem 258 minimizes leakage, and any leakage is discharged through line 304 to a suitable drain. Thus, the usage of stuffing boxes, or stem seals, is eliminated.

Valve mechanism 218 is considered a null-balance control device with a supply and bleed which are normally both closed, except when encountering an increasing or decreasing demand condition. Initial upward movement of actuator stem 258 compresses spring 262 and moves diaphragm 260 upward which compresses spring 282. Through valve seat 268, it imparts upward movement to valve stem 270, which compresses spring 276 and permits water to enter chamber 286, and via pipe 132, establish a loading pressure above the diaphragm of steam valve 26. This same pressure in chamber 286, acting against diaphragm 260, opposes spring 262, which permits the diaphragm 260 to reach a null point, where both supply valve 274 and bleed seat 268 are closed. Thus, the desired pressure for loading is locked in the system to satisfy a particular demand. An extremely small continuous bleed at seat 268 induces accuracy.

When the demand decreases, actuator stern 258 moves downward which decreases compression on spring 262, and permits diaphragm 260 and bleed seat 268 to move downward. Since supply valve 279 is already seated, it cannot move further downward, and this permits pressure in chamber 286 to bleed off to some new value where null point is established, and both supply valve 279 and bleed seat 268 are closed. Movement of the actuator stem 258 is dictated by the position of the piston 90, as previously described.

The overall result is a movable piston 90 actuated by hot water demand, which piston is precisely positioned by the differential pressure induced across same by the opening of a valve in the hot water discharge piping externally of the heat exchanger. This positioning of the piston is repeatable by the same flow demand. This piston movement is used to cause valve loader 2118 to establish a loading pressure to the top side of the diaphragm in steam valve 26. Thus, control of both steam flow and pressure is produced, and by proper adjustment, the discharge water temperature from the heat exchanger can be accurately controlled; first by blending while holding the steam pressure constant, while the steam flow is regulated by the differential diaphragm of the steam valve 26; second by increasing the steam pressure to the heat exchanger while the steam valve 26 continues to regulate the flow of steam.

The cam follower 234 has suitable threads thereon which engage with the threaded opening 290 disposed on the support member 230 and rotation of the cam follower 234 will effect movement of the cam follower in a horizontal direction relative to the support member 230. Movement of the cam follower relative to the support member 230 will control the initial set point of the pressure of the steam in the heat exchange chamber 44. The farther that the cam follower extends to the right of the support member 230, the greater the rotational movement of the support member 230 about the shaft 232 and the greater the distance the valve member 272 moves upon initial engagement of the cam follower 234 with the surface 246 of the cam member 216. Thus, the steam pressure in the heat exchange chamber 44 during initial operation of the heat exchanger may be controlled and the set point varied by rotating the cam follower 234.

The cam follower 236 is supported in the support member 230 by a member 292 which is threadably received in an opening 294 disposed in the support member 230. The support member 292 has a spring member 300 disposed therein which extends between a seat 298 and a shoulder 302 of the cam follower 236. The seat 298 is movable toward and away from the cam follower 236 by a rotating plug member 296 which is threadably supported by the member 292. Rotation of the plug 296 controls the compression of the spring 300 which controls the pivotable movement of the support member 230 when the cam follower 236 engages with the cam surface 248. When the cam follower 236 engages with the cam surface 248 the cam follower 236 will be moved to the left and the spring 300 will be compressed. When the spring is compressed a predetermined amount, further movement of the cam follower 236 to the left will effect rotation of the support member 230 to effect further movement of the valve member 272 away from the opening 280. Varying the compression of the spring 300 controls the relative movement between the cam follower 236 and the support member 230. Since the cam follower 236 always must compress the spring 300 to a predetermined pressure before movement of the support member 230 is effected, the spring 300 enables the cam 216 to act as if it had a variable slope as the magnitude of rotation of the support member 230 effected by co-action of the cam follower 236 and the cam surface 248 is directly proportional to the initial compression of the spring 300. Thus, the actuator assembly 210 works in an analogous fashion to the cam members 140 and 142 as illustrated in FIG. 2. Here, instead of the slope of the cams being variable, the rotation imparted to the support member 230 is variable. I

A cover member 310 is disposed on the upper portion of the housing 30b and is removable to provide for adjustment of the cam followers 234 and 236 relative to the support member 230. To this end the cam followers 234 and 236 include slotted end portions 235 and 297, respectively, which are operable to receive means such as a screw driver therein to effect adjustment thereof.

A drain 304 is provided below the differential diaphragm 260 and is operable to drain any fluid which might be in the chamber 306 which is located below the diaphragm 260. Generally, the chamber 306 remains free of fluid but in certain circumstances, fluid may leak around the actuator stem 258 into the chamber. The drain 304 will prevent a flow of fluid from the heating exchanger mechanism to the area surrounding the heat exchanger.

It should be apparent that the embodiment illustrated in FIGS. 4 and 5 has a similar mode of operation to the embodiment illustrated in FIGS. 1-3. However, the embodiment illustrated in FIGS. 4 and 5 eliminates all external movement of the controls to thereby prevent tampering and fouling of the mechanism. Moreover, the embodiment simplifies the cam movement in that the cam followers are adjustable rather than the cam members. Also, it should be apparent that the need for seals around the control means has been eliminated and leakage from the mechanism has been reduced by the fact that the control is internal of the heat exchanger rather than external. The internal control also adds to the aesthetic qualities of the heat exchanger. Moreover, because the springs 282, 262, and 276 cooperate to hold the valve 272 in a closed position at a nodemand condition, no bleeding of fluid to the heat exchange chamber will occur at a no-demand condition and water consumption will thereby be reduced.

It should also be apparent that steam pressure and the flow of steam to the heat exchange chamber 44 in the embodiment illustrated in FIGS. 4 and S is analogous to the flow of steam and the steam pressure utilized in the embodiment shown in FIGS. 1-3. Initial movement of piston sets up a constant steam pressure. However, the flow of steam will vary during the initial loading condition which is preferably 0 to 40 percent of the capacity of the heat exchanger mechanism as described hereinabove. While the heated water tem perature drops during this phase, blending will continue until the desired set point of the output fluid is reached. The steam condensating rate increases as the flow of water through the heat exchanger chamber 44 increases and the steam pressure will be held constant by action of the differential steam valve 26 which will increase the steam flow to the heat exchange chamber 44. At approximately 40 percent of the rated capacity of the heat exchanger the water temperature of the heated water will fall to the desired temperature. At this point, blending will cease and any further increase in flow beyond 40 percent causes the cam follower 236 to engage cam surface 248 of the cam 216 to effect an increase in the steam pressure and a further increase in the steam flow to the heat exchange chamber to thereby enable the heated water at the output location to have a desired temperature.

From the foregoing it should be apparent that a relatively simple and effective fluid handling mechanism has been provided by the present invention which is capable of heating one fluid by another fluid and controlling the output temperature of the fluid to be heated. An important economic advantage provided by the construction of the illustrated embodiments is that the basic elements thereof are easily adjustable to provide various modes of operation of the heating apparatus.

What is claimed is:

l. A heat exchanger mechanism for heating a first fluid by a second fluid comprising a housing having a heat exchange chamber located therein, a plurality of straight fluid conduits for directing the flow of the first fluid through said heat exchange chamber, a second fluid inlet for directing the second fluid into said heat exchange chamber, an outlet chamber located in said housing and from which the first fluid flows to a use location after heating thereof in said heat exchange chamber, an actuator member movable in response to a change in demand for the first fluid, cam means operatively connected with said actuator member and movable vertically in response to movement of said actuator member, a differential pressure valve for controlling the flow of the second fluid into said heat exchange chamber, a loader device for loading one side of said differential pressure valve to thereby effect a flow of the second fluid to said heat exchange chamber in response to a demand for the first fluid, means for actuating said loader device in response to movement of said cam means and including a first cam follower for imparting vertical movement to said loader device to effect a flow of the second fluid into said heat exchange chamber so that the pressure of the second fluid in said heat exchange chamber remains constant during a first mode of operation while the flow of the second fluid to said heat exchange chamber varies with the flow of the first fluid, and a second cam follower for imparting vertical movement to said loader device to effect a flow of the second fluid into said heat exchange chamber so that the pressure of the second fluid in said heat exchange chamber and the flow of the second fluid to said heat exchange chamber vary with the flow of the first fluid, said cam means being operatively connected with said first and second cam followers so that vertical movement of said cam means sequentially imparts movement to said first and second cam followers to thereby actuate said loader device to effect a flow of the second fluid to said heat exchange chamber.

2. A heat exchanger mechanism as defined in claim 1, wherein said cam means includes a first cam member for engaging with said first cam follower upon vertical movement of said first cam member to thereby impart horizontal movement to said first cam follower which imparts vertical movement to said loader device, and a second cam member for engaging with said second cam follower upon vertical movement of said second cam member to thereby impart horizontal movement to said second cam follower which imparts vertical movement to said loader device so as to actuate said loader device and provide second fluid at a variable pressure and variable flow rate to said heat exchange chamber both of which are directly proportional to the demand of the first fluid, said first and second cam members being adjustable relative to each other and to said first and second cam followers for actuating said loader device to provide for a flow of the second fluid to said heat exchange chamber which sequentially changes as the demand for the first fluid increases.

3. A heat exchanger mechanism as defined in claim 1 further including a fluid inlet chamber in said housing for directing the first fluid into said heat exchange chamber and bypass means for directing a portion of the first fluid from said inlet chamber to said outlet chamber without flowing through said heat exchange chamber.

4. A heat exchange mechanism as defined in claim 3 wherein said bypass means includes a poppet bypass valve for blending unheated first fluid from said inlet chamber with the heated first fluid as the first fluid passes toward said outlet chamber, said bypass valve having an adjustable seat the position of which is variable to control the blending of the unheated first fluid with the heated first fluid.

5. A heat exchanger mechanism as defined in claim 4 wherein said bypass valve is operable to control the blending of the unheated first fluid and the heated first fluid in response to the demand for the first fluid from the use location.

6. A heat exchanger mechanism as defined in claim 4 wherein said adjustable seat in said bypass valve is adjustable from a position located outside of said housing and wherein said bypass valve is of a unit construction and is easily removable as a unit from said housing.

7. A heat exchanger mechanism as defined in claim 1 wherein said first fluid conduit means includes a plurality of fluid conduits which are operable to direct the flow of the first fluid into and out of said heat exchange chamber four times, and further including annular baffle means operable to control the flow of the first fluid through said fluid conduits to thereby provide for said flow of the first fluid into and out of said heat exchange chamber four times.

8. A heat exchanger mechanism as defined in claim 1 wherein said actuator member includes a piston member and said valve means associated with said actuator member includes relatively movable first and second parts, said first part being operatively connected to said piston member and movable therewith and comprising a tubular conduit and said second part being disposed in said tubular conduit so that the fluid flow through said conduit is controlled by the relative position of said first and second parts.

9. A heat exchanger mechanism as defined in claim 8 wherein said tubular conduit has a frustro-conical metering surface thereon, said second part is fixed relative to said housing.

10. A heat exchanger mechanism as defined in claim 9 wherein said tubular conduit further includes an external guiding surface which acts to guide said piston member within said outlet chamber and prevent rotation of said piston member.

11. A heat exchanger mechanism as defined in claim 9 wherein said external guiding surface defines a leakoff path between said surface and said housing which provides for a small fluid flow between said surface and said housing to enable proper operation of said piston member.

12. A heat exchanger mechanism as defined in claim 8 further including biasing means for biasing said piston member to the position which said piston member occupies when there is no demand for the first fluid means.

13. A heat exchanger mechanism as defined in claim 12 wherein said biasing means includes spring means acting through the center portion of said piston member which exert biasing force on said piston member which is predetermined by varying the initial compression of said spring means.

14. A heat exchange mechanism as defined in claim 4 further including a flow control member in said housing, said flow control member being operatively connected with said actuator member and operable to control the flow of the first fluid through said bypass valve in response to movement of said actuator member.

15. A heat exchange mechanism as defined in claim 4 wherein said flow control member includes a cam operable to engage a valve stem of said bypass valve and control the flow of the first fluid through said bypass valve in response to demand for said first fluid.

16. A heat exchange mechanism as defined in claim 3 having three phases of operation including a first phase in which there is no flow of the first or second fluids, a second phase in which the pressure of the second fluid in the heat exchange chamber is constant and the first fluid flows to the outlet chamber through the first fluid conduit means and the bypass means, and a third phase wherein the pressure of the second fluid in the heat exchange chamber varies directly with the demand for the first fluid and the first fluid flows to the outlet chamber only through the first fluid conduit means.

17. A heat exchanger mechanism as defined in claim 1 wherein said cam means includes a cam member, and said first and second cam followers are sequentially engageable with said cam member and pivotable in response to engagement therewith so that vertical movement of said cam member effects pivotable movement of said first and second cam followers which impart vertical movement to said loader device to thereby actuate said loader device and effect a flow of the second fluid to said heat exchange chamber.

18. A heat exchanger mechanism as defined in claim 17 wherein engagement of said first cam follower with said cam member effects pivotable movement of a predetermined magnitude of said first cam follower to thereby effect a flow of the second fluid at a constant pressure but a variable flow rate to said heat exchange chamber and engagement of said second cam follower with said cam membereffects pivotable movement of said second cam follower which is proportional to the demand for the first fluid so that said second cam follower effects a variable pressure and a variable flow of the second fluid to said heat exchanger chamber which is directly proportional to the demand of the first fluid.

19. A heat exchanger mechanism as defined in claim 18 further including a support member for supporting said first and second cam followers, said support member being pivotally mounted so that engagement of said cam member with said first or second cam followers effects pivotable movement of said cam followers and said support member, said second cam follower being movable relative to said support member upon engagement of said cam member therewith and spring means for controlling the relative movement of said second cam follower and said support member upon engagement of said cam member with said second cam follower to thereby control the magnitude of pivotable movement of said second cam follower and said support member, said spring means being adjustable to thereby vary the relative movement of said second cam follower and said support member upon engagement of said cam member with said second cam follower, so that the magnitude of pivotal movement of said support member and said second cam follower may be varied.

20. A heat exchanger mechanism for heating a first fluid by a second fluid comprising a housing, a heat exchange chamber located in said housing and into which the second fluid is directed, an inlet chamber in said housing for directing the first fluid to said heat exchange chamber, first fluid conduit means for directing the flow of the first fluid from said inlet chamber through said heat exchange chamber, a mixing cham ber located in said housing and into which the first fluid flows from said first fluid conduit means after heating thereof in said heat exchange chamber, an outlet chamber in said housing and into which the first fluid flows from said mixing chamber, an actuator member in said outlet chamber and movable therein upon a change in demand for the first fluid, a cam member operatively associated with said actuator member and movable therewith, bypass means for directing a portion of unheated first fluid from said inlet chamber to said first fluid conduit means and including means to provide a flow of the unheated first fluid from said inlet chamber to said mixing chamber without flow through said heat exchange chamber, a flow control member located in said fluid passageway for controlling the flow of the unheated first fluid therethrough to said mixing chamber, a cam follower operatively associated with said flow control member for moving said flow control member in said passageway in response to movement of said cam member and externally mounted on said housing for adjusting said flow control member in said passageway to effect regulation of the flow of the unheated first fluid to said mixing chamber from said inlet chamber to thereby control the temperature of the first fluid in said outlet chamber.

21. A heat exchanger mechanism as defined in claim 20 further including a loader device operatively connected with said actuator member to provide for flow of the second fluid to said heat exchange chamber upon movement of said actuator member.

22. A heat exchanger mechanism as defined in claim 21 further including a first cam member operable to actuate said loader device to provide for a flow of the second fluid to said heat exchange chamber at a predetermined minimum pressure and a second cam member operable to vary the flow of the second fluid to said heat exchange chamber from said predetermined minimum pressure to a predetermined maximum pressure.

23. A heat exchange mechanism as defined in claim 22 wherein said first and second cam members are movable relative to said loader device to control the relationship between said actuator member and said loader device to provide for proper flow of the second fluid to said heat exchange chamber and to correct manufacturing inaccuracies in said heat exchanger mechanism.

24. A heat exchange mechanism as defined in claim 23 further including a cam follower mechanism movable in a horizontal direction to impart vertical movement to said loader device upon movement of said first and second cam members in a vertical direction.

25. A heat exchanger mechanism for heating a first fluid by a second fluid comprising a housing having a heat exchange chamber located therein, fluid conduit means for directing the flow of the first fluid through said heat exchange chamber, a fluid inlet for directing the second fluid into said heat exchange chamber, an outlet chamber located in said housing and from which the first fluid flows to a use location after heating thereof in said heat exchange chamber, an actuator member movable in response to a change in demand for first fluid, a cam member located internally of said heat exchanger mechanism and operatively connected with said actuator member and movable in response to movement of said actuator member, a differential pressure valve for controlling the flow of the second fluid into said heat exchange chamber, a loader device for loading one side of said differential pressure valve to thereby effect a flow of the second fluid to said heat exchange chamber in response to the demand for the first fluid, and cam follower means located internally of said heat exchanger mechanism for actuating said loader device and movable in response to movement of said cam member.

26. A heat exchanger mechanism as defined in claim 25 wherein said cam follower means includes first and second cam followers, said cam member being sequentially engageable with said first and second cam followers respectively, and engagement of said cam member with said first cam follower provides a constant pressure and variable flow of the second fluid to said heat exchange chamber and engagement of said cam member with said second cam follower provides a variable pressure and a variable flow of the second fluid to said heating exchange chamber which is directly proportional to the demand for the first fluid.

27. A heat exchanger mechanism as defined in claim 26 wherein said cam followers are pivotable in response to vertical movement of said cam member to thereby impart vertical movement to said loader device so as to activate said loader device and effect a flow of the second fluid to said heat exchange chamber, said cam member upon engagement with said first cam follower effects pivotable movement of a predetermined magnitude of said first cam follower to thereby effect a flow of the second fluid at a constant pressure but a variable flow rate to said heat exchange chamber and engagement of said second cam follower with said cam member effects pivotable movement of said second cam follower which is proportional to the demand for the first fluid so that said second cam follower effects a variable pressure and a variable flow of the second fluid to said heat exchanger chamber which is directly proportional to the demand for the first fluid.

28. A heat exchanger mechanism as defined in claim 27 further including a support member for supporting said first and second cam followers, said support member being pivotally mounted so that engagement of said cam member with said first or second cam followers effects pivotable movement of said cam followers and said support member, said second cam follower being movable relative to said support member upon engagement of said cam member therewith and spring means for controlling the relative movement of said second cam follower and said support member upon engagement of said cam member with said second cam follower to thereby control the magnitude of pivotable movement of said second cam follower and said support member, said spring means being adjustable to thereby vary the relative movement of said second cam follower and said support member upon engagement of said cam member with said second cam follower, so that the magnitude of pivotal movement of said support member and said second cam follower may be varied. 

1. A heat exchanger mechanism for heating a first fluid by a second fluid comprising a housing having a heat exchange chamber located therein, a plurality of straight fluid conduits for directing the flow of the first fluid through said heat exchange chamber, a second fluid inlet for directing the second fluid into said heat exchange chamber, an outlet chamber located in said housing and from which the first fluid flows to a use location after heating thereof in said heat exchange chamber, an actuator member movable in response to a change in demand for the first fluid, cam means operatively connected with said actuator member and movable vertically in response to movement of said actuator member, a differential pressure valve for controlling the flow of the second fluid into said heat exchange chamber, a loader device for loading one side of said differential pressure valve to thereby effect a flow of the second fluid to said heat exchange chamber in response to a demand for the first fluid, means for actuating said loader device in response to movement of said cam means and including a first cam follower for imparting vertical movement to said loader device to effect a flow of the second fluid into said heat exchange chamber so that the pressure of the second fluid in said heat exchange chamber remains constant during a first mode of operation while the flow of the second fluid to said heat exchange chamber varies with the flow of the first fluid, and a second cam follower for imparting vertical movement to said loader device to effect a flow of the second fluid into said heat exchange chamber so that the pressure of the second fluid in said heat exchange chamber and the flow of the second fluid to said heat exchange chamber vary with the flow of the first fluid, said cam means being operatively connected with said first and second cam followers so that vertical movement of said cam means sequentially imparts movement to said first and second cam followers to thereby actuate said loader device to effect a flow of the second fluid to said heat exchange chamber.
 2. A heat exchanger mechanism as defined in claim 1, wherein said cam means includes a first cam member for engaging with said first cam follower upon vertical movement of said first cam member to thereby impart horizontal movement to said first cam follower which imparts vertical movement to said loader device, and a second cam member for engaging with said second cam follower upon vertical movement of said second cam member to thereby impart horizontal movement to said second cam follower which imparts vertical movement to said loader device so as to actuate said loader device and provide second fluid at a variable pressure and variable flow rate to said heat exchange chamber both of which are directly proportional to the demand of the first fluid, said first and second cam members being adjustable relative to each other and to said first and second cam followers for actuating said loader device to provide for a flow of the second fluid to said heat exchange chamber which sequentially changes as the demand for the first fluid increases.
 3. A heat exchanger mechanism as defined in claim 1 further including a fluid inlet chamber in said housing for directing the first fluid into said heat exchange chamber and bypass means for directing a portion of the first fluid from said inlet chamber to said outlet chamber without flowing through said heat exchange chamber.
 4. A heat exchange mechanism as defined in claim 3 wherein said bypass means includes a poppet bypass valve for blending unheated first fluid from said inlet chamber with the heated first fluid as the first fluid passes toward said outlet chamber, said bypass valve having an adjustable seat the position of which is variable to control the blending of the unheated first fluid with the heated first fluid.
 5. A heat exchanger mechanism as defined in claim 4 wherein said bypass valve is oPerable to control the blending of the unheated first fluid and the heated first fluid in response to the demand for the first fluid from the use location.
 6. A heat exchanger mechanism as defined in claim 4 wherein said adjustable seat in said bypass valve is adjustable from a position located outside of said housing and wherein said bypass valve is of a unit construction and is easily removable as a unit from said housing.
 7. A heat exchanger mechanism as defined in claim 1 wherein said first fluid conduit means includes a plurality of fluid conduits which are operable to direct the flow of the first fluid into and out of said heat exchange chamber four times, and further including annular baffle means operable to control the flow of the first fluid through said fluid conduits to thereby provide for said flow of the first fluid into and out of said heat exchange chamber four times.
 8. A heat exchanger mechanism as defined in claim 1 wherein said actuator member includes a piston member and said valve means associated with said actuator member includes relatively movable first and second parts, said first part being operatively connected to said piston member and movable therewith and comprising a tubular conduit and said second part being disposed in said tubular conduit so that the fluid flow through said conduit is controlled by the relative position of said first and second parts.
 9. A heat exchanger mechanism as defined in claim 8 wherein said tubular conduit has a frustro-conical metering surface thereon, said second part is fixed relative to said housing.
 10. A heat exchanger mechanism as defined in claim 9 wherein said tubular conduit further includes an external guiding surface which acts to guide said piston member within said outlet chamber and prevent rotation of said piston member.
 11. A heat exchanger mechanism as defined in claim 9 wherein said external guiding surface defines a leak-off path between said surface and said housing which provides for a small fluid flow between said surface and said housing to enable proper operation of said piston member.
 12. A heat exchanger mechanism as defined in claim 8 further including biasing means for biasing said piston member to the position which said piston member occupies when there is no demand for the first fluid means.
 13. A heat exchanger mechanism as defined in claim 12 wherein said biasing means includes spring means acting through the center portion of said piston member which exert biasing force on said piston member which is predetermined by varying the initial compression of said spring means.
 14. A heat exchange mechanism as defined in claim 4 further including a flow control member in said housing, said flow control member being operatively connected with said actuator member and operable to control the flow of the first fluid through said bypass valve in response to movement of said actuator member.
 15. A heat exchange mechanism as defined in claim 4 wherein said flow control member includes a cam operable to engage a valve stem of said bypass valve and control the flow of the first fluid through said bypass valve in response to demand for said first fluid.
 16. A heat exchange mechanism as defined in claim 3 having three phases of operation including a first phase in which there is no flow of the first or second fluids, a second phase in which the pressure of the second fluid in the heat exchange chamber is constant and the first fluid flows to the outlet chamber through the first fluid conduit means and the bypass means, and a third phase wherein the pressure of the second fluid in the heat exchange chamber varies directly with the demand for the first fluid and the first fluid flows to the outlet chamber only through the first fluid conduit means.
 17. A heat exchanger mechanism as defined in claim 1 wherein said cam means includes a cam member, and said first and second cam followers are sequentially engageable with said cam member and pivotable in response To engagement therewith so that vertical movement of said cam member effects pivotable movement of said first and second cam followers which impart vertical movement to said loader device to thereby actuate said loader device and effect a flow of the second fluid to said heat exchange chamber.
 18. A heat exchanger mechanism as defined in claim 17 wherein engagement of said first cam follower with said cam member effects pivotable movement of a predetermined magnitude of said first cam follower to thereby effect a flow of the second fluid at a constant pressure but a variable flow rate to said heat exchange chamber and engagement of said second cam follower with said cam member effects pivotable movement of said second cam follower which is proportional to the demand for the first fluid so that said second cam follower effects a variable pressure and a variable flow of the second fluid to said heat exchanger chamber which is directly proportional to the demand of the first fluid.
 19. A heat exchanger mechanism as defined in claim 18 further including a support member for supporting said first and second cam followers, said support member being pivotally mounted so that engagement of said cam member with said first or second cam followers effects pivotable movement of said cam followers and said support member, said second cam follower being movable relative to said support member upon engagement of said cam member therewith and spring means for controlling the relative movement of said second cam follower and said support member upon engagement of said cam member with said second cam follower to thereby control the magnitude of pivotable movement of said second cam follower and said support member, said spring means being adjustable to thereby vary the relative movement of said second cam follower and said support member upon engagement of said cam member with said second cam follower, so that the magnitude of pivotal movement of said support member and said second cam follower may be varied.
 20. A heat exchanger mechanism for heating a first fluid by a second fluid comprising a housing, a heat exchange chamber located in said housing and into which the second fluid is directed, an inlet chamber in said housing for directing the first fluid to said heat exchange chamber, first fluid conduit means for directing the flow of the first fluid from said inlet chamber through said heat exchange chamber, a mixing chamber located in said housing and into which the first fluid flows from said first fluid conduit means after heating thereof in said heat exchange chamber, an outlet chamber in said housing and into which the first fluid flows from said mixing chamber, an actuator member in said outlet chamber and movable therein upon a change in demand for the first fluid, a cam member operatively associated with said actuator member and movable therewith, bypass means for directing a portion of unheated first fluid from said inlet chamber to said first fluid conduit means and including means to provide a flow of the unheated first fluid from said inlet chamber to said mixing chamber without flow through said heat exchange chamber, a flow control member located in said fluid passageway for controlling the flow of the unheated first fluid therethrough to said mixing chamber, a cam follower operatively associated with said flow control member for moving said flow control member in said passageway in response to movement of said cam member and externally mounted on said housing for adjusting said flow control member in said passageway to effect regulation of the flow of the unheated first fluid to said mixing chamber from said inlet chamber to thereby control the temperature of the first fluid in said outlet chamber.
 21. A heat exchanger mechanism as defined in claim 20 further including a loader device operatively connected with said actuator member to provide for flow of the second fluid to said heat exchange chamber upon movement of said actuator member.
 22. A heat exchangeR mechanism as defined in claim 21 further including a first cam member operable to actuate said loader device to provide for a flow of the second fluid to said heat exchange chamber at a predetermined minimum pressure and a second cam member operable to vary the flow of the second fluid to said heat exchange chamber from said predetermined minimum pressure to a predetermined maximum pressure.
 23. A heat exchange mechanism as defined in claim 22 wherein said first and second cam members are movable relative to said loader device to control the relationship between said actuator member and said loader device to provide for proper flow of the second fluid to said heat exchange chamber and to correct manufacturing inaccuracies in said heat exchanger mechanism.
 24. A heat exchange mechanism as defined in claim 23 further including a cam follower mechanism movable in a horizontal direction to impart vertical movement to said loader device upon movement of said first and second cam members in a vertical direction.
 25. A heat exchanger mechanism for heating a first fluid by a second fluid comprising a housing having a heat exchange chamber located therein, fluid conduit means for directing the flow of the first fluid through said heat exchange chamber, a fluid inlet for directing the second fluid into said heat exchange chamber, an outlet chamber located in said housing and from which the first fluid flows to a use location after heating thereof in said heat exchange chamber, an actuator member movable in response to a change in demand for first fluid, a cam member located internally of said heat exchanger mechanism and operatively connected with said actuator member and movable in response to movement of said actuator member, a differential pressure valve for controlling the flow of the second fluid into said heat exchange chamber, a loader device for loading one side of said differential pressure valve to thereby effect a flow of the second fluid to said heat exchange chamber in response to the demand for the first fluid, and cam follower means located internally of said heat exchanger mechanism for actuating said loader device and movable in response to movement of said cam member.
 26. A heat exchanger mechanism as defined in claim 25 wherein said cam follower means includes first and second cam followers, said cam member being sequentially engageable with said first and second cam followers respectively, and engagement of said cam member with said first cam follower provides a constant pressure and variable flow of the second fluid to said heat exchange chamber and engagement of said cam member with said second cam follower provides a variable pressure and a variable flow of the second fluid to said heating exchange chamber which is directly proportional to the demand for the first fluid.
 27. A heat exchanger mechanism as defined in claim 26 wherein said cam followers are pivotable in response to vertical movement of said cam member to thereby impart vertical movement to said loader device so as to activate said loader device and effect a flow of the second fluid to said heat exchange chamber, said cam member upon engagement with said first cam follower effects pivotable movement of a predetermined magnitude of said first cam follower to thereby effect a flow of the second fluid at a constant pressure but a variable flow rate to said heat exchange chamber and engagement of said second cam follower with said cam member effects pivotable movement of said second cam follower which is proportional to the demand for the first fluid so that said second cam follower effects a variable pressure and a variable flow of the second fluid to said heat exchanger chamber which is directly proportional to the demand for the first fluid.
 28. A heat exchanger mechanism as defined in claim 27 further including a support member for supporting said first and second cam followers, said support member being pivotally mounted so that engagement of said cam member with said first or sEcond cam followers effects pivotable movement of said cam followers and said support member, said second cam follower being movable relative to said support member upon engagement of said cam member therewith and spring means for controlling the relative movement of said second cam follower and said support member upon engagement of said cam member with said second cam follower to thereby control the magnitude of pivotable movement of said second cam follower and said support member, said spring means being adjustable to thereby vary the relative movement of said second cam follower and said support member upon engagement of said cam member with said second cam follower, so that the magnitude of pivotal movement of said support member and said second cam follower may be varied. 